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mirror of https://github.com/python/cpython.git synced 2024-11-25 01:20:47 +01:00
cpython/Modules/main.c
Steve Dower 99fcf15052
bpo-45582: Port getpath[p].c to Python (GH-29041)
The getpath.py file is frozen at build time and executed as code over a namespace. It is never imported, nor is it meant to be importable or reusable. However, it should be easier to read, modify, and patch than the previous code.

This commit attempts to preserve every previously tested quirk, but these may be changed in the future to better align platforms.
2021-12-03 00:08:42 +00:00

732 lines
18 KiB
C

/* Python interpreter main program */
#include "Python.h"
#include "pycore_call.h" // _PyObject_CallNoArgs()
#include "pycore_initconfig.h" // _PyArgv
#include "pycore_interp.h" // _PyInterpreterState.sysdict
#include "pycore_pathconfig.h" // _PyPathConfig_ComputeSysPath0()
#include "pycore_pylifecycle.h" // _Py_PreInitializeFromPyArgv()
#include "pycore_pystate.h" // _PyInterpreterState_GET()
/* Includes for exit_sigint() */
#include <stdio.h> // perror()
#ifdef HAVE_SIGNAL_H
# include <signal.h> // SIGINT
#endif
#if defined(HAVE_GETPID) && defined(HAVE_UNISTD_H)
# include <unistd.h> // getpid()
#endif
#ifdef MS_WINDOWS
# include <windows.h> // STATUS_CONTROL_C_EXIT
#endif
/* End of includes for exit_sigint() */
#define COPYRIGHT \
"Type \"help\", \"copyright\", \"credits\" or \"license\" " \
"for more information."
#ifdef __cplusplus
extern "C" {
#endif
/* --- pymain_init() ---------------------------------------------- */
static PyStatus
pymain_init(const _PyArgv *args)
{
PyStatus status;
status = _PyRuntime_Initialize();
if (_PyStatus_EXCEPTION(status)) {
return status;
}
PyPreConfig preconfig;
PyPreConfig_InitPythonConfig(&preconfig);
status = _Py_PreInitializeFromPyArgv(&preconfig, args);
if (_PyStatus_EXCEPTION(status)) {
return status;
}
PyConfig config;
PyConfig_InitPythonConfig(&config);
/* pass NULL as the config: config is read from command line arguments,
environment variables, configuration files */
if (args->use_bytes_argv) {
status = PyConfig_SetBytesArgv(&config, args->argc, args->bytes_argv);
}
else {
status = PyConfig_SetArgv(&config, args->argc, args->wchar_argv);
}
if (_PyStatus_EXCEPTION(status)) {
goto done;
}
status = Py_InitializeFromConfig(&config);
if (_PyStatus_EXCEPTION(status)) {
goto done;
}
status = _PyStatus_OK();
done:
PyConfig_Clear(&config);
return status;
}
/* --- pymain_run_python() ---------------------------------------- */
/* Non-zero if filename, command (-c) or module (-m) is set
on the command line */
static inline int config_run_code(const PyConfig *config)
{
return (config->run_command != NULL
|| config->run_filename != NULL
|| config->run_module != NULL);
}
/* Return non-zero if stdin is a TTY or if -i command line option is used */
static int
stdin_is_interactive(const PyConfig *config)
{
return (isatty(fileno(stdin)) || config->interactive);
}
/* Display the current Python exception and return an exitcode */
static int
pymain_err_print(int *exitcode_p)
{
int exitcode;
if (_Py_HandleSystemExit(&exitcode)) {
*exitcode_p = exitcode;
return 1;
}
PyErr_Print();
return 0;
}
static int
pymain_exit_err_print(void)
{
int exitcode = 1;
pymain_err_print(&exitcode);
return exitcode;
}
/* Write an exitcode into *exitcode and return 1 if we have to exit Python.
Return 0 otherwise. */
static int
pymain_get_importer(const wchar_t *filename, PyObject **importer_p, int *exitcode)
{
PyObject *sys_path0 = NULL, *importer;
sys_path0 = PyUnicode_FromWideChar(filename, wcslen(filename));
if (sys_path0 == NULL) {
goto error;
}
importer = PyImport_GetImporter(sys_path0);
if (importer == NULL) {
goto error;
}
if (importer == Py_None) {
Py_DECREF(sys_path0);
Py_DECREF(importer);
return 0;
}
Py_DECREF(importer);
*importer_p = sys_path0;
return 0;
error:
Py_XDECREF(sys_path0);
PySys_WriteStderr("Failed checking if argv[0] is an import path entry\n");
return pymain_err_print(exitcode);
}
static int
pymain_sys_path_add_path0(PyInterpreterState *interp, PyObject *path0)
{
_Py_IDENTIFIER(path);
PyObject *sys_path;
PyObject *sysdict = interp->sysdict;
if (sysdict != NULL) {
sys_path = _PyDict_GetItemIdWithError(sysdict, &PyId_path);
if (sys_path == NULL && PyErr_Occurred()) {
return -1;
}
}
else {
sys_path = NULL;
}
if (sys_path == NULL) {
PyErr_SetString(PyExc_RuntimeError, "unable to get sys.path");
return -1;
}
if (PyList_Insert(sys_path, 0, path0)) {
return -1;
}
return 0;
}
static void
pymain_header(const PyConfig *config)
{
if (config->quiet) {
return;
}
if (!config->verbose && (config_run_code(config) || !stdin_is_interactive(config))) {
return;
}
fprintf(stderr, "Python %s on %s\n", Py_GetVersion(), Py_GetPlatform());
if (config->site_import) {
fprintf(stderr, "%s\n", COPYRIGHT);
}
}
static void
pymain_import_readline(const PyConfig *config)
{
if (config->isolated) {
return;
}
if (!config->inspect && config_run_code(config)) {
return;
}
if (!isatty(fileno(stdin))) {
return;
}
PyObject *mod = PyImport_ImportModule("readline");
if (mod == NULL) {
PyErr_Clear();
}
else {
Py_DECREF(mod);
}
}
static int
pymain_run_command(wchar_t *command)
{
PyObject *unicode, *bytes;
int ret;
unicode = PyUnicode_FromWideChar(command, -1);
if (unicode == NULL) {
goto error;
}
if (PySys_Audit("cpython.run_command", "O", unicode) < 0) {
return pymain_exit_err_print();
}
bytes = PyUnicode_AsUTF8String(unicode);
Py_DECREF(unicode);
if (bytes == NULL) {
goto error;
}
PyCompilerFlags cf = _PyCompilerFlags_INIT;
cf.cf_flags |= PyCF_IGNORE_COOKIE;
ret = PyRun_SimpleStringFlags(PyBytes_AsString(bytes), &cf);
Py_DECREF(bytes);
return (ret != 0);
error:
PySys_WriteStderr("Unable to decode the command from the command line:\n");
return pymain_exit_err_print();
}
static int
pymain_run_module(const wchar_t *modname, int set_argv0)
{
PyObject *module, *runpy, *runmodule, *runargs, *result;
if (PySys_Audit("cpython.run_module", "u", modname) < 0) {
return pymain_exit_err_print();
}
runpy = PyImport_ImportModule("runpy");
if (runpy == NULL) {
fprintf(stderr, "Could not import runpy module\n");
return pymain_exit_err_print();
}
runmodule = PyObject_GetAttrString(runpy, "_run_module_as_main");
if (runmodule == NULL) {
fprintf(stderr, "Could not access runpy._run_module_as_main\n");
Py_DECREF(runpy);
return pymain_exit_err_print();
}
module = PyUnicode_FromWideChar(modname, wcslen(modname));
if (module == NULL) {
fprintf(stderr, "Could not convert module name to unicode\n");
Py_DECREF(runpy);
Py_DECREF(runmodule);
return pymain_exit_err_print();
}
runargs = PyTuple_Pack(2, module, set_argv0 ? Py_True : Py_False);
if (runargs == NULL) {
fprintf(stderr,
"Could not create arguments for runpy._run_module_as_main\n");
Py_DECREF(runpy);
Py_DECREF(runmodule);
Py_DECREF(module);
return pymain_exit_err_print();
}
_Py_UnhandledKeyboardInterrupt = 0;
result = PyObject_Call(runmodule, runargs, NULL);
if (!result && PyErr_Occurred() == PyExc_KeyboardInterrupt) {
_Py_UnhandledKeyboardInterrupt = 1;
}
Py_DECREF(runpy);
Py_DECREF(runmodule);
Py_DECREF(module);
Py_DECREF(runargs);
if (result == NULL) {
return pymain_exit_err_print();
}
Py_DECREF(result);
return 0;
}
static int
pymain_run_file_obj(PyObject *program_name, PyObject *filename,
int skip_source_first_line)
{
if (PySys_Audit("cpython.run_file", "O", filename) < 0) {
return pymain_exit_err_print();
}
FILE *fp = _Py_fopen_obj(filename, "rb");
if (fp == NULL) {
// Ignore the OSError
PyErr_Clear();
PySys_FormatStderr("%S: can't open file %R: [Errno %d] %s\n",
program_name, filename, errno, strerror(errno));
return 2;
}
if (skip_source_first_line) {
int ch;
/* Push back first newline so line numbers remain the same */
while ((ch = getc(fp)) != EOF) {
if (ch == '\n') {
(void)ungetc(ch, fp);
break;
}
}
}
struct _Py_stat_struct sb;
if (_Py_fstat_noraise(fileno(fp), &sb) == 0 && S_ISDIR(sb.st_mode)) {
PySys_FormatStderr("%S: %R is a directory, cannot continue\n",
program_name, filename);
fclose(fp);
return 1;
}
// Call pending calls like signal handlers (SIGINT)
if (Py_MakePendingCalls() == -1) {
fclose(fp);
return pymain_exit_err_print();
}
/* PyRun_AnyFileExFlags(closeit=1) calls fclose(fp) before running code */
PyCompilerFlags cf = _PyCompilerFlags_INIT;
int run = _PyRun_AnyFileObject(fp, filename, 1, &cf);
return (run != 0);
}
static int
pymain_run_file(const PyConfig *config)
{
PyObject *filename = PyUnicode_FromWideChar(config->run_filename, -1);
if (filename == NULL) {
PyErr_Print();
return -1;
}
PyObject *program_name = PyUnicode_FromWideChar(config->program_name, -1);
if (program_name == NULL) {
Py_DECREF(filename);
PyErr_Print();
return -1;
}
int res = pymain_run_file_obj(program_name, filename,
config->skip_source_first_line);
Py_DECREF(filename);
Py_DECREF(program_name);
return res;
}
static int
pymain_run_startup(PyConfig *config, int *exitcode)
{
int ret;
if (!config->use_environment) {
return 0;
}
PyObject *startup = NULL;
#ifdef MS_WINDOWS
const wchar_t *env = _wgetenv(L"PYTHONSTARTUP");
if (env == NULL || env[0] == L'\0') {
return 0;
}
startup = PyUnicode_FromWideChar(env, wcslen(env));
if (startup == NULL) {
goto error;
}
#else
const char *env = _Py_GetEnv(config->use_environment, "PYTHONSTARTUP");
if (env == NULL) {
return 0;
}
startup = PyUnicode_DecodeFSDefault(env);
if (startup == NULL) {
goto error;
}
#endif
if (PySys_Audit("cpython.run_startup", "O", startup) < 0) {
goto error;
}
FILE *fp = _Py_fopen_obj(startup, "r");
if (fp == NULL) {
int save_errno = errno;
PyErr_Clear();
PySys_WriteStderr("Could not open PYTHONSTARTUP\n");
errno = save_errno;
PyErr_SetFromErrnoWithFilenameObjects(PyExc_OSError, startup, NULL);
goto error;
}
PyCompilerFlags cf = _PyCompilerFlags_INIT;
(void) _PyRun_SimpleFileObject(fp, startup, 0, &cf);
PyErr_Clear();
fclose(fp);
ret = 0;
done:
Py_XDECREF(startup);
return ret;
error:
ret = pymain_err_print(exitcode);
goto done;
}
/* Write an exitcode into *exitcode and return 1 if we have to exit Python.
Return 0 otherwise. */
static int
pymain_run_interactive_hook(int *exitcode)
{
PyObject *sys, *hook, *result;
sys = PyImport_ImportModule("sys");
if (sys == NULL) {
goto error;
}
hook = PyObject_GetAttrString(sys, "__interactivehook__");
Py_DECREF(sys);
if (hook == NULL) {
PyErr_Clear();
return 0;
}
if (PySys_Audit("cpython.run_interactivehook", "O", hook) < 0) {
goto error;
}
result = _PyObject_CallNoArgs(hook);
Py_DECREF(hook);
if (result == NULL) {
goto error;
}
Py_DECREF(result);
return 0;
error:
PySys_WriteStderr("Failed calling sys.__interactivehook__\n");
return pymain_err_print(exitcode);
}
static int
pymain_run_stdin(PyConfig *config)
{
if (stdin_is_interactive(config)) {
config->inspect = 0;
Py_InspectFlag = 0; /* do exit on SystemExit */
int exitcode;
if (pymain_run_startup(config, &exitcode)) {
return exitcode;
}
if (pymain_run_interactive_hook(&exitcode)) {
return exitcode;
}
}
/* call pending calls like signal handlers (SIGINT) */
if (Py_MakePendingCalls() == -1) {
return pymain_exit_err_print();
}
if (PySys_Audit("cpython.run_stdin", NULL) < 0) {
return pymain_exit_err_print();
}
PyCompilerFlags cf = _PyCompilerFlags_INIT;
int run = PyRun_AnyFileExFlags(stdin, "<stdin>", 0, &cf);
return (run != 0);
}
static void
pymain_repl(PyConfig *config, int *exitcode)
{
/* Check this environment variable at the end, to give programs the
opportunity to set it from Python. */
if (!config->inspect && _Py_GetEnv(config->use_environment, "PYTHONINSPECT")) {
config->inspect = 1;
Py_InspectFlag = 1;
}
if (!(config->inspect && stdin_is_interactive(config) && config_run_code(config))) {
return;
}
config->inspect = 0;
Py_InspectFlag = 0;
if (pymain_run_interactive_hook(exitcode)) {
return;
}
PyCompilerFlags cf = _PyCompilerFlags_INIT;
int res = PyRun_AnyFileFlags(stdin, "<stdin>", &cf);
*exitcode = (res != 0);
}
static void
pymain_run_python(int *exitcode)
{
PyObject *main_importer_path = NULL;
PyInterpreterState *interp = _PyInterpreterState_GET();
/* pymain_run_stdin() modify the config */
PyConfig *config = (PyConfig*)_PyInterpreterState_GetConfig(interp);
/* ensure path config is written into global variables */
if (_PyStatus_EXCEPTION(_PyPathConfig_UpdateGlobal(config))) {
goto error;
}
if (config->run_filename != NULL) {
/* If filename is a package (ex: directory or ZIP file) which contains
__main__.py, main_importer_path is set to filename and will be
prepended to sys.path.
Otherwise, main_importer_path is left unchanged. */
if (pymain_get_importer(config->run_filename, &main_importer_path,
exitcode)) {
return;
}
}
if (main_importer_path != NULL) {
if (pymain_sys_path_add_path0(interp, main_importer_path) < 0) {
goto error;
}
}
else if (!config->isolated) {
PyObject *path0 = NULL;
int res = _PyPathConfig_ComputeSysPath0(&config->argv, &path0);
if (res < 0) {
goto error;
}
if (res > 0) {
if (pymain_sys_path_add_path0(interp, path0) < 0) {
Py_DECREF(path0);
goto error;
}
Py_DECREF(path0);
}
}
pymain_header(config);
pymain_import_readline(config);
if (config->run_command) {
*exitcode = pymain_run_command(config->run_command);
}
else if (config->run_module) {
*exitcode = pymain_run_module(config->run_module, 1);
}
else if (main_importer_path != NULL) {
*exitcode = pymain_run_module(L"__main__", 0);
}
else if (config->run_filename != NULL) {
*exitcode = pymain_run_file(config);
}
else {
*exitcode = pymain_run_stdin(config);
}
pymain_repl(config, exitcode);
goto done;
error:
*exitcode = pymain_exit_err_print();
done:
Py_XDECREF(main_importer_path);
}
/* --- pymain_main() ---------------------------------------------- */
static void
pymain_free(void)
{
_PyImport_Fini2();
/* Free global variables which cannot be freed in Py_Finalize():
configuration options set before Py_Initialize() which should
remain valid after Py_Finalize(), since
Py_Initialize()-Py_Finalize() can be called multiple times. */
_PyPathConfig_ClearGlobal();
_Py_ClearStandardStreamEncoding();
_Py_ClearArgcArgv();
_PyRuntime_Finalize();
}
static int
exit_sigint(void)
{
/* bpo-1054041: We need to exit via the
* SIG_DFL handler for SIGINT if KeyboardInterrupt went unhandled.
* If we don't, a calling process such as a shell may not know
* about the user's ^C. https://www.cons.org/cracauer/sigint.html */
#if defined(HAVE_GETPID) && !defined(MS_WINDOWS)
if (PyOS_setsig(SIGINT, SIG_DFL) == SIG_ERR) {
perror("signal"); /* Impossible in normal environments. */
} else {
kill(getpid(), SIGINT);
}
/* If setting SIG_DFL failed, or kill failed to terminate us,
* there isn't much else we can do aside from an error code. */
#endif /* HAVE_GETPID && !MS_WINDOWS */
#ifdef MS_WINDOWS
/* cmd.exe detects this, prints ^C, and offers to terminate. */
/* https://msdn.microsoft.com/en-us/library/cc704588.aspx */
return STATUS_CONTROL_C_EXIT;
#else
return SIGINT + 128;
#endif /* !MS_WINDOWS */
}
static void _Py_NO_RETURN
pymain_exit_error(PyStatus status)
{
if (_PyStatus_IS_EXIT(status)) {
/* If it's an error rather than a regular exit, leave Python runtime
alive: Py_ExitStatusException() uses the current exception and use
sys.stdout in this case. */
pymain_free();
}
Py_ExitStatusException(status);
}
int
Py_RunMain(void)
{
int exitcode = 0;
pymain_run_python(&exitcode);
if (Py_FinalizeEx() < 0) {
/* Value unlikely to be confused with a non-error exit status or
other special meaning */
exitcode = 120;
}
pymain_free();
if (_Py_UnhandledKeyboardInterrupt) {
exitcode = exit_sigint();
}
return exitcode;
}
static int
pymain_main(_PyArgv *args)
{
PyStatus status = pymain_init(args);
if (_PyStatus_IS_EXIT(status)) {
pymain_free();
return status.exitcode;
}
if (_PyStatus_EXCEPTION(status)) {
pymain_exit_error(status);
}
return Py_RunMain();
}
int
Py_Main(int argc, wchar_t **argv)
{
_PyArgv args = {
.argc = argc,
.use_bytes_argv = 0,
.bytes_argv = NULL,
.wchar_argv = argv};
return pymain_main(&args);
}
int
Py_BytesMain(int argc, char **argv)
{
_PyArgv args = {
.argc = argc,
.use_bytes_argv = 1,
.bytes_argv = argv,
.wchar_argv = NULL};
return pymain_main(&args);
}
#ifdef __cplusplus
}
#endif